The Collaborative International Dictionary of English v.0.48:

Play \Play\, v. i. [imp. & p. p. Played; p. pr. & vb. n.
   Playing.] [OE. pleien, AS. plegian, plegan, to play, akin
   to plega play, game, quick motion, and probably to OS. plegan
   to promise, pledge, D. plegen to care for, attend to, be
   wont, G. pflegen; of unknown origin. [root]28. Cf. Plight,
   n.]
   1. To engage in sport or lively recreation; to exercise for
      the sake of amusement; to frolic; to spot.
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            As Cannace was playing in her walk.   --Chaucer.
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            The lamb thy riot dooms to bleed to-day,
            Had he thy reason, would he skip and play! --Pope.
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            And some, the darlings of their Lord,
            Play smiling with the flame and sword. --Keble.
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   2. To act with levity or thoughtlessness; to trifle; to be
      careless.
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            "Nay," quod this monk, "I have no lust to pleye."
                                                  --Chaucer.
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            Men are apt to play with their healths. --Sir W.
                                                  Temple.
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   3. To contend, or take part, in a game; as, to play ball;
      hence, to gamble; as, he played for heavy stakes.
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   4. To perform on an instrument of music; as, to play on a
      flute.
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            One that . . . can play well on an instrument.
                                                  --Ezek.
                                                  xxxiii. 32.
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            Play, my friend, and charm the charmer. --Granville.
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   5. To act; to behave; to practice deception.
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            His mother played false with a smith. --Shak.
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   6. To move in any manner; especially, to move regularly with
      alternate or reciprocating motion; to operate; to act; as,
      the fountain plays.
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            The heart beats, the blood circulates, the lungs
            play.                                 --Cheyne.
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   7. To move gayly; to wanton; to disport.
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            Even as the waving sedges play with wind. --Shak.
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            The setting sun
            Plays on their shining arms and burnished helmets.
                                                  --Addison.
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            All fame is foreign but of true desert,
            Plays round the head, but comes not to the heart.
                                                  --Pope.
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   8. To act on the stage; to personate a character.
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            A lord will hear your play to-night.  --Shak.
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            Courts are theaters where some men play. --Donne.
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   To play into a person's hands, to act, or to manage
      matters, to his advantage or benefit.

   To play off, to affect; to feign; to practice artifice.

   To play upon.
      (a) To make sport of; to deceive.
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                Art thou alive?
                Or is it fantasy that plays upon our eyesight.
                                                  --Shak.
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      (b) To use in a droll manner; to give a droll expression
          or application to; as, to play upon words.
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The Collaborative International Dictionary of English v.0.48:

Playing \Play"ing\,
   a. & vb. n. of Play.
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   Playing cards. See under Card.
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WordNet (r) 3.0 (2006):

playing
    n 1: the act of playing a musical instrument
    2: the action of taking part in a game or sport or other
       recreation
    3: the performance of a part or role in a drama [syn: acting,
       playing, playacting, performing]

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "playing":
   acting, aflicker, aping, betting, bickering, blinking, buffoonery,
   business, cardsharping, casting lots, characterization, coquetry,
   dabbling, dalliance, dallying, dancing, dumb show, embodiment,
   enacting, enactment, fiddling, flashing, flickering, flickery,
   flicky, flirtation, fluttering, fluttery, fooling, fooling around,
   gag, gambling, gaming, ham, hammy acting, hazarding, hoke, hokum,
   idling, imitation, impersonation, incarnation, jerking off,
   kidding around, lambent, loitering, masquerade, messing around,
   mimesis, mimicking, mimicry, miming, monkeying, monkeying around,
   mummery, overacting, pantomime, pantomiming, patter, performance,
   performing, personation, personification, piddling, play,
   playacting, playing around, portrayal, posing, pottering,
   projection, puttering, quivering, quivery, representation, risking,
   slapstick, smattering, sortition, speculation, sporting,
   stage business, stage directions, stage presence, staking,
   stroboscopic, stunt, taking a role, tinkering, toying, trifling,
   wagering, wavering, wavery